Refinances on mortgages held by Fannie Mae and Freddie Mac showed double digit increases in August, but analysts differ on whether or not a refi wave has hit. Fannie Mae reported a 27% monthly increase in aggregate prepayment rates on 30-year mortgages. In the same month, Freddie reported a 32% increase, according to JPMorgan. According to Barclays Capital, the speed of these refinancing numbers picked up considerably. “Specifically, after subtracting housing turnover and delinquency buyouts, we estimate that 30y FNMA/FHLMC [Fannie/Freddie] refinancing volume nearly doubled in the past two months (July to September report),” according to a research note from Barclays Capital. BarCap analysts added that an increase of this magnitude was absent from the similar indices because the survey captures only slightly more than half of the retail mortgage applications and that some loans that closed in July were carried over into August. “The bottom-line is, we are not convinced that the latest report marks the start of a refinancing wave,” according to BarCap. Based on the Fannie and Freddie reports, though, JPMorgan analysts called August the beginning of “Refi 2010.” “This report reinforces our view that the threat of a ‘conventional’ refi event is squarely aimed at the lower coupons 4.5s and 5s and to a lesser extent 5.5s,” according to the report. Write to Jon Prior.